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Title: On the valence fluctuation in the early actinide metals

In this study, recent X-ray measurements suggest a degree of valence fluctuation in plutonium and uranium intermetallics. We are applying a novel scheme, in conjunction with density functional theory, to predict 5f configuration fractions of states with valence fluctuations for the early actinide metals. For this purpose we perform constrained integer f-occupation calculations for the α phases of uranium, neptunium, and plutonium metals. For plutonium we also investigate the δ phase. The model predicts uranium and neptunium to be dominated by the f 3 and f 4 configurations, respectively, with only minor contributions from other configurations. For plutonium (both α and δ phase) the scenario is dramatically different. Here, the calculations predict a relatively even distribution between three valence configurations. The δ phase has a greater configuration fraction of f 6 compared to that of the α phase. The theory is consistent with the interpretations of modern X-ray experiments and we present resonant X-ray emission spectroscopy results for α-uranium.
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [2] ;  [3] ;  [3] ;  [4] ;  [4] ;  [4]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Report Number(s):
LLNL-JRNL-672996; LA-UR-17-24461
Journal ID: ISSN 0368-2048
Grant/Contract Number:
AC52-07NA27344; AC02-05CH11231; AC52-06NA25396
Accepted Manuscript
Journal Name:
Journal of Electron Spectroscopy and Related Phenomena
Additional Journal Information:
Journal Volume: 207; Journal Issue: C; Journal ID: ISSN 0368-2048
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; valence fluctuations; actinides; X-ray emission spectroscopy; density functional theory
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1252027; OSTI ID: 1409777